1. Field of the Invention
The present invention relates to an image forming apparatus using an electrophotographic system and its cleaner unit, and a cleaner unit replacement method of the image forming apparatus.
2. Description of the Related Art
At present, in an image forming apparatus using an electrophotographic system, a so-called cartridge system is widely known in which a photoconductive body, a charger, and a cleaner are integrally constructed into a unit, and it is replaced as a structure attachable to and detachable from the image forming apparatus. This cartridge often integrally includes a developing device as well, and further, there is also an example in which all parts, including a toner tank and a waste toner tank, are integrated. The merits of the cartridge system as stated above are that the maintenance can be easily performed by the user and by merely replacing the single unit, it is not necessary that a serviceman or the like makes a business trip and makes a replacement, and further, when the apparatus is stopped due to failure caused by the unit, since it can be easily returned by merely replacing the unit, down time can be reduced.
However, there is a problem in the cartridge system as stated above. Since the whole unit is collectively replaced, a part which has not reached the replacement cycle is also replaced. For example, in the case of a cartridge in which a photoconductive body, a charger and a cleaner are integrally constructed, when the cleaner is worn down, even if the photoconductive body is still in a usable state, both are replaced, and consequently, the cost of consumables is increased.
Further, in recent years, the replacement cycle of the photoconductive body becomes long by the emergence of the photoconductive body using A-Si (Amorphous Silicon), or the organic photoconductive body in which the surface layer having high hardness is provided on its surface. On the other hand, with respect to the cleaner part, the structure of the cleaner itself must be complicated in order to prolong the life, and in association with this, the cleaner part becomes large, and it is difficult to apply the cleaner part to a small diameter photoconductive body.
Then, in patent document 1 (JP-A-6-118857) and patent document 2 (JP-A-10-31404), there is proposed a method in which a cleaner part is constructed to be attachable to and detachable from a photoconductive body, and the user can easily replace the cleaner part.
This is such that blade cleaning means is constructed to be attachable to and detachable from the photoconductive body, and at that time, toner spillage from a cleaner opening at the time of detachment, which is a problem, is prevented. Specifically, the opening of the blade cleaner portion of the cleaner unit is covered with a sheet-like member, and since the opening itself is closed by this, the toner spillage is greatly reduced.
However, in the related art, after all, the blade cleaner has a large opening, and it is strictly difficult to cover the opening with the sheet at the same time as the detachment from the photoconductive body, and it can not be avoided that the toner spillage occurs although the amount is slight.
Besides, in the blade cleaner, contact accuracy to the photoconductive body is delicate, a slight shift causes defective cleaning, and it is difficult to form an easily replaceable structure.